Integrator and torque amplifier therefor



Oct. 10, 1950 D. H. NELSON 2,525,147

IIITEGRATOR AND TORQUE AMPLIFIER THEREFOR POWER PRE /2| AMPLIFIERIAMPLIFIIER l WATT HOUR M ETER 24 1 VOLTAGE I co:

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owan PRE' AMPLIFIER AMPLIFIER INVENTOR :25 12a o.|-|. NELSON Oct. 10,1950 NELSON 2,525,147

. iNTEGRATOR AND TORQUE AMPLIFIER THEREFOR Filed Au 14, 1946 2Sheets-Sheet 2 PHASE PHASE 'PRE SHIFTER SHIFTEB AMPLIFIER POWERAMPLIFIER 258 259 POWER POWER AMPLIFIER AMPLIFIER WATT-HOUR d METER I224 23o I I 2Io 1 r VOLTAGE I ILlIlII/(n-n llIl \WJ-LMETER DISC. U\ 2'6I CURRENT coIL IDC \ PHASE PHASE SHIFTER SHIFTER SOURCE H SINGLE PHASEFIG.4

INVENTOR V D.H.NELSON BY ZUC.

ATTORN EY Patented Oct. l0, 1950 INTEGRATOR AND TORQUE AMPLIFIERTHEREFOR Dale H. Nelson, Southampton, N. Y., assignor to The WesternUnion Telegraph Company, New York, N. Y., a corporation of New YorkApplication Augu t 14, 1946, Serial No. 690,447

This invention relates to improvements in integrators and torqueamplifiers therefor, and more particularly to improvements inintegrators with respect to time, of quantities expressable by voltageor current, and torque amplifiers therefor.

Watthour meters per se serve as efficient integrators of voltage andcurrent, with respect to time, for some purposes, but due to the lack ofmechanical power afiorded by such devices, their utility has beenlimited. It is not possible to use the disk of such a meter as asource-of mechanical power with any appreciable load without seriouslyaffecting the accuracy of the device for the normal purposes. Theimposition of a train of gears for meter purposes imposes a slight loadon a watthour meter disk, but this load does not materially reduce theaccuracy to such an extent as to render-the'meter unsuitable forcommercial purposes. However, for precision measurements involving themeasurement of a small fraction of one revolution of the disk, such agear train is wholly inadequate due to the high gear reduction andbacklash. A further disadvantage is the still relatively small torqueavailable, even after a considerable gear reduction.

An object of the present invention is to provide an improved integratorof the watthour meter type in which the accuracy is not impaired by theutilization of thedisk thereof for mechanical power purposes.

Another object of the invention is to provide an integrator of theforegoing character, in which an extremely large torque amplification ofthe torque developed by the disk is obtained, without recourse to gearreduction, and without imposing any load on the disk.

Another object of the invention is to provide an integrator of theforegoing character in which no load is placed upon the disk thereof,the integration carried out by the device being indicated otherwise thanby means directly mechanically driven by the disk.

Another object of the invention is to provide an integrator of thecharacter before mentioned in which a self-synchronous motor is drivenby voltage controlled by a watthour meter disk whereby theself-synchronous motor can be driven in accordance with the rotation ofthe disk.

Another object of the invention is to provide an integrator in which thewatthour meter disk has its periphery formed with alternate teeth andgaps for the purpose of interrupting a light beam or beams traveling toa photoelectric cell,

4 Claims. (Cl. 250-233) the output of which is amplified and used toexcite the rotor of a self-synchronous motor, the stator windings ofwhich are excited by multiphase alternating current.

A further object of the invention is to provide an integrator of thecharacter before described in which a synchronously interrupted lightbeam can be further interrupted by a watthour meter disk for providingchanges of phase of the resultant voltage developed by a photoelectriccell thereby to cause rotation of a self-synchronous motor in accordancewith such variations in I phase.

A still further object of the invention is to provide an integrator asbefore described in which the rays of light from sources energized bymultiphase alternating current are variously intercepted by a watthourmeter disk to cause the generation of voltage, the phase of which variesin accordance with the position of the meter disk, for exciting therotor of the self-synchronous motor.

In carrying out the foregoing and other objects of the invention, use ismade of an induction type watthour meter, the disk of which has itsperipheral edge provided with alternate gaps or slots and teeth ofcorresponding width. In

.one form of the invention such a disk is associated with a plurality.of sources of light rays which are energized respectively by the phasesof a source of multi-phase alternating current. In the preferred form ofthe invention the source of light rays are three in number to beenergized by three-phase alternating current. These sources of lightrays are so related to the watthour meter disk that a gap or slot in theperipheral edge thereof is of sufficient width as to permit the passage,at any position of the disk, of the equivalent of half of the total fluxvalue of the light rays from all three sources. The rays not interceptedby the watthour meter disk are directedto the photoelectric cell, theoutput of which is conducted to a suitable pro-amplifier, thence to asuitable power amplifier, and the power amplifier in turn is connectedto the rotor winding of a self-synchronous motor, the stator windings ofwhich are connected to the same (i. e. synchronous) three-phase sourceof alternating current. With this arrangement it follows that as long asthe disc is stationary the rotor of the self-synchronous motor will besupplied with current of a constant phase relative to that of the statorwindings, with the result that the motor is held stationary. However,when the disk rotates, the phase of the alternating voltage generated bythe photoelectric cell varies in accordance with the position of thedisk, resulting in either progressively advancing or retarding the phaseof the rotor current relative to that of the stator windings of theself-synchronous motor, with a consequent progressive rotation of therotor of this motor in one direction or the other dependent on the rateand direction of the disk motion. The rotor of the selfsynchronous motorthus reproduces the motion of the disk, executing one completerevolution of the rotor for each tooth and gap on the disk.

In another form of the invention, rays of light from a source, energizedpreferably by direct current, are synchronously interrupted to providelight rays of a frequency corresponding to the frequency of the sourceof supply used to energize the stator windings of the self-synchronousmotor. Again, a watthour meter disk is utilized having its edge providedwith alternate teeth and gaps of equal width, which disk is positionedto cause the teeth to lie in the path of part of the rays beforementioned. Again, as long as the disk is stationary, the rays of lightsynchronously interrupted and impinging upon a photoelectric cell causethe generation of alternating voltage which can be amplified andsupplied to the rotor of a self-synchronous motor. When the disk remainsstationary, the frequency of the current in the rotor is the same as thesynchronous light ray interrupter, and the rotor therefore remainsstationary. When the disk moves the changing relationship of the diskteeth either progressively advances or retards the phase of theinterrupted light rays, causing the rotor of the self-synchronous motorto progressively rotate either in one direction or the other. In eitherform of the invention the self -synchronous motor can be utilized todrive any desired mechanisms within the rated power of such motor.

Other features, objects and advantages of the invention will becomeapparent by referenceto the following detailed description of the accompanying drawings illustrating the same, wherein:

Fig. 1 is a schematic circuit diagram including parts of one embodimentof the invention;

'Fig, 2 is an enlarged plan view of a fragment of a disk takensubstantially on the line 2-2 of" Fig. 1;

Fig. 3 is a view similar to Fig. l of a modification of the invention;and

Fig. 4 is a similar View of a further modficaton.

Referring now to the drawings, and particularly to Figs. 1 and 2, itindicates generally the disk of a conventional induction type watthourmeter, which disk is mounted on a shaft l I supported by bearings in theusual manner. The peripheral edge of disk I is provided with a pluralityof teeth 52 separated by gaps or slots I4, which gaps or slots havewidths substantially equal to the widths of the teeth 12. The teeth andgaps may be of any desired number, but in the form of the inventionherein described both the teeth and gaps are twelve in numberrespectively. illustrates the current coil, while It illustrates thevoltage coil either one or both of which may be used to control therotation of the disk I 0. Associated with the disk [flare three sourcesof light rays in the nature of small neon bulbs I1, I8 and I9. Thesebulbs are supplied with current by the three phases of a sixty cyclesupply. The bulbs are positioned on an arccorresponding to the arc ofcurvature of the edge portion of disk it having the teeth and gapsorslots therein. Aligned with the bulbs in position to intercept therays of light directed therefrom is a photocell 20, the output of whichis fed to a preamplifier 2i and thence to a power amplifier 22 of anydesired types. The amplified output of the amplifier 2! is directed bylines 23 to the rotor winding of a self-synchronous motor 24. The statorwindings of this motor are supplied with alternating current by thethree phases of a sixty cycle threephase power source.

Preferably the bulbs IT, IS and is are mounted within three chimneys 25,26, and 21, respectively, which are of such length and size as to directthe rays of light from these bulbs towards the photocell, insubstantially parallel fashion. The chimneys, as shown in Fig. 2, aremounted to conform to the arc of curvature of the disk Ill, with eachchimney occupying a space approximately equal to two-thirds either of atooth l2 of a slot i4. Due to this positioning, it follows that with thedisk It! stationary and with the teeth and slots thereof in any positionrelative to the three chimneys, half of the effective rays from thethree bulbs will be unmasked to be directed to the cell 26 through asuitable lens 30, which lens serves to concentrate the rays on theactive electrode of the cell. In actual practice the bulbs f7, f8 and isare maintained constantly energized by a suitable source of directcurrent at such a potential that each bulb is in stable operatingcondition. In addition to this constant energization of the bulbs, eachthereof is modulated by its respective phase of alternating current, sothat each bulb is cyclically brought to a point of hi h light emanationalternating with low light emanation maintained above the minimumoperating voltage point of the bulb. Thus, so far as the out: put of thephotoelectric cell 20 is concerned for each bulb the current generatedthereby is of substantially sine wave character with the median linerepresented by the condition of the bulb due to the D. C. energizationthereof. Lamps l1, l8 and I9 all carry the same 60 cycle frequencymodulation of their light fiux outputs. However, since their electricalmodulations are degrees apart for a three phase system, it follows thatthe modulation of the light flux outputswill also be 120 degrees apart.Furthermore, it follows that the total modulated voltage from thephotoelectric cell 20 will be the vectorial sum of the modulatedvoltages due to each light flux source.

Considering the disk in the position shown in Fig. 2, it will be seenthat at any moment the modulated rays of light passing through the slotoverlying bulb l! and part of bulb l8 will represent the vectorial sumof the full modulated value of bulb I! plus one-half that of bulb l8,with the output of cell 20 in turn in the nature of a sine waverepresenting this vectorial sum. With the disk stationary, this outputof tube 29 will vary cyclically at sixty cycles so that the powersupplied to the rotor of motor 26 by the amplifier 2| will be of sixtycycle character, and will have a temporarily fixed phase relationship tothe sixty cycle three-phase alternating current supplied to the statorwindings of this motor.

The motor 24, as before mentioned, is a selfsynchronous motor, which isof a phase sensitive nature whereby any variation in phase of theexcitation of the rotor relative to that ofthe stator windings Willcause a movement of the rotor to bring it into synchronism with thestator windings. If the power supplied to the rotor is of the samefrequency as that supplied to the stator windings, the rotor andconsequently the driving shaft of the motor will remain stationary.

However, if the phase of the current exciting: the

. direction of phase change, a corresponding number of angular degrees.Consequently, if the phase relation of the rotor exciting current isshifted through 360 electrical degrees per second in an additivedirection, the result'will be that the rotor of .the motor will rotateone revolution per second. Similarly, if the phase change .is in thesubtractive direction the rotor will rotate in the opposite directionone rotation persecond.

Due to this character of the self-synchronous motor, it follows thatshould the disk Ill be rotated under the impetus provided by thewindings I5 and I6, such rotation will either advance or retard thephase relation of the voltage developed by cell 20 from the lamps II, I8and I9 in accordance with the position of the disk. Rotation of thisdisk in one direction will advance this phase relation, while rotationin theopposite direction will retard the same. Should the disk berotated in one direction (Fig. 2) through an arc encompassing one toothI2 and one slot I4, the effect. will be to advance the phase of theoutput of cell 20 through 360 electrical degrees, causing the rotor ofmotor 24 to rotate through 360 or one complete revolution thereof. Withthe disk I!) being provided with twelve teeth and twelve slots, it willbe apparent that.

one revolution per second of this disc will cause twelve revolutions persecond of the rotor of motor 24, and further that any change of positionof disk II) will be immediately reflected by a change of position ofthis motor. Furthermore, any reversal of direction of rotation of thedisk results in a corresponding reversal of direction of rotation of themotor. The shaft of the motor, therefore, can be connected in ansuitable manner to any mechanism which it may be desirable to be driven,such as an indicating device or any other mechanism, control of whichshould be in accordance with the integration with respect to time, ofquantities expressible by voltage or current. v

In the embodiment of the invention shown in Fig. 3, III! illustrates awatthour meter disk 'similarto that shown at Iii in Fig. l, suchdiskbeing rotatably mounted on a shaft III to be driven by coils H5 and H6.Instead, however, of utilizing three sources of light rays as in theprevious embodiment, use is made of a single source of light rays H7 inthe'nature of a light bulb to be energized by direct current.

Interposed between the bulb III and the disk I I9 is a light chopper inthe nature of a disk I I8, the periphery of which is provided with teethand slots similar to those of the disk III Disk II8, which is mounted ona shaft H9, is driven by a suitable motor (not shown) at such rate as tocause the rays of light fromsource II'I.to be interrupted synchronouslyat a rate corresponding to the frequency of the alternating current usedin a manner to be described later. In the arrangement shown, the disc II8 is provided with twelve teeth and twelve slots, so that if this diskis rotated at the rate of five revolutions per second, the beam of lightrays will be interrupted sixty times per second, or in synchronism witha' sixty cycle supply source. Use is also made of a ing of the motorI25.

photocell I20 in line to receive rays of light from source Ill, with alens I2I interposed for the purpose of insuring parallelism of the rays.The output of cell I20 is fed to a pre-amplifier I22 6 and thenceto apower amplifier I23' which in turn is connected by lines I24 to therotor of a self-synchronous motor I25, the stator windings of which areenergized by the three phases of a suitable three-phase power supplysource.

The teeth and slots of disk I III (twelve in number respectively) are ofsuch width relative to the photocell I20, that one tooth and one slotcombine to present an area representing the effective range ofthephotocell. Consequently, should the disk IIO be at rest while thesynchronous chopper comprising disk [I 8 is rotating at its constantsynchronous speed of rotation, the result will be the imposition on thephotocell I2ll of lightrays of cyclically, varying intensity, thevariation being carried out at the rate of sixty cycles per second. Dueto such light rays, the photocell generates voltage, amplified bypre-amplifier I22 and power amplifier I23, which is in the nature ofalternating current .and is supplied to the rotor wind- This motor issimilar to that previously described and, as before, so long as thephase of the current through the rotor is temporarily fixed with respectto that through the stator windings, the rotor remains stationary.Should the disk I I0, however, be moved under the control of the coilsH5 and II6, the phase relation of the generated alternating voltage (byphotocell I20) is either progressively advanced or retarded relative tothe statorsupply source, with the result that the motor is alsoprogressively rotated either in one direction or the other. For example,if the chopper disk is rotating in a counterclockwise direction and thedisk H6 is moved in a clockwise direction, the result would be to retardthe phase of the rotor current in proportion to the motion of disk IIB.For further example, if the disk III) is rotated at such speed that onetooth and one slot cross the path of light rays in one second, thesynchronous motor will be rotated through one revolution each second,and since under the prescribed conditions the phase relation is of aretarded nature the motor will be rotated in one direction. Should,however, the disk III) be moved also in a counterclockwise direction,the effect would be to advance the phase relation of the rotor current,causing the motor I25 to be moved in the opposite direction. Again, asbefore described, the motor I25 can be connected to any suitablemechanism, either for indicating purposes or for obtaining automaticactuation of such mechanism as may be desirable, particularly controlmechanism wherein it is desired that the operation thereof be governedby integration, with re-.- spect to time, of quantities expressible byvoltage or current.

In the modification of the invention shown in Fig. 4, 2 I0 illustrates awatthour meter disk similar to those before described, such disk beingrotatably mounted on shaft 2 I I to be driven by coils 2I5 and 2I6.Three bulbs 2I1,2I8 and 2L9, similar to those described in connectionwith Fig. l, are mounted in substantially the same relation as in thatfigure. The bulbs 2II, 2I8 and 2I9 are energized from a suitable sourceof 60 cycle, single phase current with any one bulb, such as bulb 2I8,being-energized directly thereby. Bulb 2I'I and bulb 2I9, however, haveinterposed in the energizing circuit of, each phase shifters 250 and25!, respectively, These phase shifters are constructed in conventionalfashion and are so related to the source of power that the phase of thecurrent energizing 'the respective lamp can be shifted relative to thereference phase so that,

7 for example, lamp 2 l 9 is energized by current advanced 120 relativeto the current energizing 2l8, while that energizing lamp 2|! is eitheradvanced 240 or retarded 120. The overall efiect is similar to thatdescribed in connection with Fig. 1.

Aligned with the bulb in position to intercept the rays of lighttherefrom is a photocell 229, the output of which is fed to apre-amplifier: 22! and thence through phase shifters and poweramplifiers and through a single power amplifier to the stator windingsof a synchronous motor 224. As shown inv the drawings one winding ofthis motor is energized directlyfrom the pre-amplifier through a poweramplifier 255 while phase shifters 255 and 257 are interposed betweenpreamplifier 22! and the power amplifiers 258 and 259 which areconnected to the other two windings of the motor 224. These phaseshifters 256 and 251 are provided for the same purposes as the phaseshifters 250 and 251 so that with the shifter 255 being constructed toadvance the. voltage output of pre-amplifier 25| 120 and phase shifter25! being constructed either to advance these voltages 240 or retard thesame 120 the final result will be that the three windings of the statorof motor 224 will have impressed thereon voltages of B-phase characterwith 120 interval the phases thereof.

In this modification, the operation is substantially the same as thatpreviously described in that voltages are developed by the photoelectriccell 229 in accordance with the intensit of the light flux directed tothis photoelectric cell through condensing lens 230. The phase of thevoltages generated by cell 220 will vary in accordance with movement ofthe disk 2|0 which has teeth therein exactly as described in disk l0.However, instead of utilizing the single phase voltages of varyingcharacter to energize the rotor of a self-synchronous motor suchvoltages are amplified and branches thereof shifted uniformly describedprovides novel arrangements whereby the torque of a membercan beamplified without imposing a load on such member.

What is claimed is:

1. The method of amplifying the torque of a movable member whichcomprises energizing a plurality of sources of light rays each withenergy of a different phase relative to that of the other sources,directing light flux from said sources upon a light sensitive element tocause said element to generate alternating voltages, modulating thelight flux from said sources in accordance with movement of said memberto cause said element to vary the phase of said alternating voltages,and impressing said voltages upon a phase sensitive device to controlactuation thereof.

2 Apparatus of the character described comprising a plurality of sOurcesof light flux, a light sensitive device in the path of said light fiux,a. movable member having parts thereof in said path of light flux, meansfor energizing said sources with multi-phase energy to vary theintensity of said light fiux thereby to cause said device to generatealternating voltages, movement of said member modulating said light fiuxto cause said device to vary the phase of said Voltages, and a phasesensitive device actuated by said voltages.

3. Apparatus of the character described comprising a plurality ofsources of light flux energized by multi-phase energy, a light sensitivedevice in the path of said light flux, a movable member having partsthereof in said path of light fiux intercepting part of said flux tocause said device to generate alternating voltages, movement of saidmember modualting said light fiux to cause said device to vary the phaseof said voltages, and a phase sensitive device actuated by saidvoltages.

4. Apparatus of the character described comprising a plurality ofsources of light flux constantly energized to a predetermined degree, alight sensitive device in the path of said light flux, a movable memberhaving parts thereof in said path of light fiuX, means for energizingsaid sources with multi-phase energy to vary the intensity of said lightflux thereb to cause said device to generate alternating voltages,movement of said member modulating said light flux to cause said deviceto vary the phase of said voltages, and a phase sensitive deviceactuated by said voltages.

DALE H. NELSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,912,139 Hough May 30, 19331,916,356 Bohner July 4, 1933 2,065,421 Bernarde Dec. 22, 1936 2,167,484Berry July 25, 1939 2,411,147 Cooley Nov. 19, 1946 2,451,971 Oman Oct.19, 1948 FOREIGN PATENTS Number Country Date 46,165 France Dec. 23, 1935

